In Northern Areas of Pakistan lies the junction of three greatest mountain ranges of the world, Himalaya, Hindukush and Karakoram. This part of land is the best sample of evaluation and changes in making of Earth. Out of 30 highest peaks of the world, ten are located here. As these mountains are famous for beautiful valleys, snow packed peaks, waterfalls and orchards, at the same time these are known for unpredicted/unannounced snow/land slides, earthquakes and floods.
Karakoram Highway is the main artery in the communication system of Northern Areas which links Pakistan with China. This highway is a masterpiece, as far as man made structures are concerned. It is also known as 8th wonder of the world.
Three hours journey from Gilgit towards East, there is beautiful valley of Hunza, known for its fruit and scenic beauty.
On 4 Jan 2010, 19 km East of Hunza, where a small natural lake Attabad existed, came a huge rock slide which engulfed 2 km area of KKH and blocked Hunza River completely. All type of traffic on KKH to and from China was disconnected. In next few days, Attabad Lake was converted into a dam with 130-200 m depth and 22 km length. If this dam was left to be further filled, it would have resulted into a “Dam burst scenario” and would have been the worst disaster of the world. In case of the dam burst, the flow of water down hill towards Gilgit would have been so massive that most of the bridges and villages astride river Hunza would have been completely washed away.
Due to Attabad disaster the villages of Gojal, Attabad and Aminabad were vacated. Gilmit village and 25 km of KKH, including important Shishkat Bridge also vanished under water. The habitants located upstream of Attabad were cut off from rest of the world.
On 20 Jan 2010 Government of Pakistan asked Frontier Works Organisation (FWO) to control the situation. FWO mobilized its maximum resources to deal with this natural disaster. It constructed spillway immediately to curtail further storage of water into the lake, thus reducing the overall damage by 50%.
Experts from World Bank Dr. Richard Hughes, Dr. David Petlay and Mr. Allessandro Palinieri visited the site to ascertain nature of the calamity and they appreciated the efforts by FWO in damage control.
Planning Commission of Pakistan consulted various Engineering experts of the World including China and USA. Chinese suggested trench mortar technique to deepen the spillway by 30 meter with the cost of 2.4 billion rupees and many years were required to complete it. Second method was reduction of water through syphon method in which a number of pipes were to be used to drain out the water but this technique was also not suitable due to nature of terrain / mountains. Keeping in view the make and type of the mountains none of the foreign firms was ready to undertake this task.
FWO suggested reduction of water by 30 m through controlled blasting costing only Rs. 500 million. Rock blasting and earthwork was estimated 28 million cubic feet. Oct to May was suitable to reduce the water as in other months, volume and speed (current) of the water would not permit any type of work.
Following are a few factors for which none of the International Engineers firm, (including China, US and Korea) was ready to undertake this responsibility despite heavy amounts of income involved.:-
Make and type of the mountains dictates excessive and heavy land slides as compared to any other mountainous area.
Temperature in winters would fall below -15ºC thus making it very difficult for men and machinery to work.
Very less space is available on disaster site so required men and machinery can not work simultaneously.
Due to nature of terrain, logistic support is extremely difficult and expensive.
Planning Commission awarded the contract of lowering the water level by 30 m, to FWO on Oct 2010. By May 2011 the water level was reduced by 4 m.
During the low flow season from Oct 2011 to May 2012, FWO was successful in lowering the lake water by 16 meter, much faster than the estimated time given to Planning Division. Till date FWO has sacrificed three precious lives including one Colonel for the accomplishment of his sacred task.